A wireless communication system has been widely developed to provide various kinds of communication services such as voice and data. Generally, the wireless communication system is a multiple access system that can support communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of the multiple access system include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and a single carrier frequency division multiple access (SC-FDMA) system.
In the wireless communication system, there are time-zone boundaries more than tens of thousands of miles long over the globe. FIG. 1 illustrates time zones of the United States. Referring to FIG. 1, the geographic length of the time-zone boundary between Pacific Time zone and Mountain Time zone is more than 1,500 miles in the United States.
A User Equipment (UE) in the boundary cell (which is the cell one or more of which boundary cells have different time zone value) has a high likelihood to be handed over to the next cell which belongs to a different time zone. Referring to FIG. 2, the UE 1 moves from the Mountain Time Zone to the Pacific Time Zone when the UE 1 has made a series of moves crossing the boundary of Time Zones from one to another or back and forth.
Under this situation, some of smartphones (i.e. a UE) have an option that the user can choose whether to use “Automatic update” on the time zone value whenever it receives “Automatic time zone” information indicating the time zone has been changed. In this case, if the user sets the “Automatic time zone” menu, the time of the UE is automatically changed according to the “time zone” information. However, it is difficult to recognize the time has been changed because there is no notification to the user whether the time is changed.
In addition, if the user does not set the “Automatic time zone” menu option, the time zone of the UE is not changed until the user of the UE manually resets the time zone. In this case, it is cumbersome to the user because the user has to manually reset the time of UE according to the “Automatic time zone” information.
Moreover, in aspect of the network, the specification on a Network Identity and Time Zone (NITZ) does not specify a Man-Machine Interface such that the user located near the boundary may not recognize what the current time zone when the said user unknowingly passes the boundary between the two adjacent time zones. Therefore, the time zone of the UE is automatically changed without any notice to the user, and this can lead confusion of the user due to misunderstanding of the changed time which is displayed based on the unknowingly changed time zone near the boundary of the time zones.